Antenna apparatus

ABSTRACT

An antenna apparatus is disclosed. The antenna apparatus is structured by a ground plate that is shaped like a plate, and a feeding unit that is formed by a plate-like member, the feeding unit extending from the ground plate generally perpendicular to the ground plate at a predetermined angle to the ground plate for a predetermined length.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an antenna apparatus, andespecially relates to an antenna apparatus that has a ground plate thatis shaped like a plate, and a feeding unit that extends from the groundplate in a direction generally perpendicular to the ground plate at apredetermined offset angle for a predetermined length.

2. Description of the Related Art

In recent years and continuing, radio communications technology usingUWB (ultra-wide band) attracts attention since radar positioning andcommunications with a large transmission capacity are possible. As forUWB, the U.S. FCC (Federal Communications Commission) allowed use of a3.1-10.6 GHz band in 2002.

Communications at UWB are performed by sending a pulse signal using awide frequency band. Accordingly, an antenna apparatus used for UWB hasto be capable of receiving a wide band signal.

For UWB communications, at least in the 3.1-10.6 GHz frequency bandapproved by the FCC, an antenna apparatus consisting of a ground plateand a feeding unit is proposed (Non-patent Reference 1).

FIG. 1A shows a structure of a conventional antenna apparatus 10.

The antenna apparatus 10 shown in FIG. 1A includes a feeding unit 12installed on a ground plate 11, the feeding unit 12 being shaped like aninverted cone.

In addition, the inverted cone that constitutes the feeding unit 12 isset up so that its side may form an angle θ to an axis 13 thatperpendicularly intersects the ground plate 11. A desired property isobtained by the angle θ.

An antenna apparatus 20 shown in FIG. 1B includes a feeding unit 22 inthe shape of a teardrop that includes an inverted cone 22 a, and asphere 22 b inscribed in the inverted cone 22 a on the ground plate 11.

[Non-Patenting Reference 1]

“An Omnidirectional and Low-VSWR Antenna for the FCC-Approved UWBFrequency Band”, Takuya Taniguchi and Takehiko Kobayashi (Tokyo DenkiUniversity) (Announced on Mar. 22, 2003 at classroom B201) TheElectronic Information Communication Society 2003 B-1-133.

[Problem(s) to be Solved by the Invention]

However, since the conventional wideband-antenna apparatus is structuredby the feeding unit having one of the inverted cone shape and theteardrop shape on the ground plate, the dimensions tend to be great.Then, an antenna apparatus that is smaller and thinner is desired.

SUMMARY OF THE INVENTION

Accordingly, a general object of the present invention is to provide anantenna apparatus that is small and thin, substantially obviating one ormore of the problems caused by the limitations and disadvantages of therelated art.

Features and advantages of the present invention are set forth in thedescription that follows, and in part will become apparent from thedescription and the accompanying drawings, or may be learned by practiceof the invention according to the teachings provided in the description.Objects as well as other features and advantages of the presentinvention will be realized and attained by an antenna apparatusparticularly pointed out in the specification in such full, clear,concise, and exact terms as to enable a person having ordinary skill inthe art to practice the invention.

[Means for Solving the Problem]

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, theinvention provides the antenna apparatus as follows.

An aspect of the present invention provides the antenna apparatusincluding a ground plate that is shaped like a plate, and a feeding unitthat extends from the ground plate in a direction that intersectsperpendicularly with the ground plate for a predetermined length in apredetermined angle, wherein the feeding unit is shaped like a plate.

According to another aspect of the present invention, an upper part ofthe plate constituting the feeding unit is sliced and removed, the upperpart opposing the ground plate.

According to another aspect of the present invention, the feeding unitis installed with its face being slanted relative to the ground plate.

According to another aspect of the present invention, the feeding unitis installed such that it can rotate in directions parallel to theground plate (about an axis perpendicular to the ground plate).

According to another aspect of the present invention, the feeding unitis attached to the ground plate.

According to another aspect of the present invention, the ground plateand the feeding unit are structured by a pattern for the ground plateand a pattern for the feeding unit, respectively, formed on a flexibleprinted wiring board, wherein the part of the pattern for the feedingunit is bent in reference to the part of the pattern for the groundplate such that the feeding unit is structured as extending from theground plate perpendicular to the ground plate for a predeterminedlength.

[Effect of the Invention]

As described above, according to the present invention, since thefeeding unit is structured by a plate that extends from the groundplate, the antenna apparatus can be made small and thin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are block diagrams of examples of conventional antennaapparatuses;

FIG. 2 is a perspective diagram of the first embodiment of the presentinvention;

FIG. 3 is an orthographic projection of the first embodiment of thepresent invention;

FIG. 4 is a perspective diagram of the second embodiment of the presentinvention;

FIG. 5 is an orthographic projection of the second embodiment of thepresent invention;

FIG. 6 is a perspective diagram of the third embodiment of the presentinvention;

FIG. 7 is an orthographic projection of the third embodiment of thepresent invention;

FIG. 8 is a perspective diagram of the fourth embodiment of the presentinvention;

FIG. 9 is an orthographic projection of the fourth embodiment of thepresent invention;

FIG. 10 is an exploded perspective diagram of a fixing part 432;

FIG. 11 is a perspective diagram of the fifth embodiment of the presentinvention;

FIG. 12 is an orthographic projection of the fifth embodiment of thepresent invention; and

FIGS. 13A, 13B and 13C are perspective drawings for explaining amanufacturing method of an antenna apparatus 500.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention are describedwith reference to the accompanying drawings.

The First Embodiment

FIG. 2 is a perspective diagram of an antenna apparatus 100 according tothe first embodiment of the present invention, and FIG. 3 is anorthographic projection thereof.

The antenna apparatus 100 of the present embodiment includes a printedwiring board 101, an antenna unit 102, and an RF circuit unit 103.

The printed wiring board 101 is made from dielectrics such as resin andceramics, for example, FR-4, and CEM3, on the surface of whichelectronic parts 111 are mounted. The electronic parts 111 mounted onthe printed wiring board 101 are connected by an electrically conductivepattern 112 (illustration omitted), and constitute the RF circuit unit103. The RF circuit unit 103 is connected to the antenna unit 102 by amicrostrip line 113 formed on the printed wiring board 101.

The antenna unit 102 includes a ground plate 121 and the feeding unit122.

The ground plate 121 is constituted by electrically conductive patterns121 a and 121 b formed on the printed wiring board 101. The electricallyconductive patterns 121 a and 121 b are connected to a groundingpattern.

The feeding unit 122 includes a feeding plate 131 and a fixing part 132.The feeding plate 131 is made by fabricating a metal plate. Here, theshape of the feeding plate 131 is shown as nearly being a circle, whichis approximately the same as the conventional cross-section of thefeeding units 12 and 22 taken along a plane that contains the centeraxis of the feeding units 12 and 22. The feeding plate 131 may be shapedin any form, such as a teardrop and a circle, so long as it can transmitand receive an electric wave of a desired frequency band.

When the feeding plate 131 is designed for communications at a frequencybetween 3.1 and 10.6 GHz that is the frequency band of UWB, the angle θ(see FIG. 5) of the periphery section to the centerline C is set atbetween 40° and 80°, and the height H is set at about 25 mm. Here, theheight H is set at approximately λ/4 of the minimum frequency used fortransmission and reception. For example, if the frequency between 3.1and 10.6 GHz should be covered, λ is set at the wavelength correspondingto 3.1 GHz.

Further, the width W of the ground plate 121 is set up so that groundplate 121 may become slightly greater than the bottom shape of thefeeding plate 122 in the width W directions.

By setting up as described above, the peak value of VSWR can be madesmaller than 3.0 in the 3.1-10.6 GHz range that is the frequency band ofUWB.

The fixing part 132 is formed at the lower part of the feeding plate131, and at the end in the direction indicated by arrow Z2 by welding,or by fabricating in one body with the feeding plate 131. The fixingpart 132 has nail sections 132 a that extend in the arrow Z2 direction.The nail sections 132 a are placed into respective through-holes 101 aformed on the printed wiring board 101 at end in the direction indicatedby arrow X2, are bent onto the rear surface of the printed wiring board101 in the arrow Z2 direction, and are fixed to the printed wiring board101 by soldering. In this manner, the feeding plate 131 is arrangedstraight up in the arrow Z1 direction, and fixed to the printed wiringboard 101.

The fixing part 132 is soldered to the printed wiring board 101 at theend of the microstrip line 113 formed on the printed wiring board 101.The microstrip line 113 is formed in the directions of the arrows X1 andX2 between the electrically conductive patterns 121 a and 121 b. Theother edge of the microstrip line 113 is connected to the RF circuitunit 103.

According to this embodiment, the feeding unit 121 is made small andthin as compared with the conventional case where the feeding unit isstructured by an inverted cone. Accordingly, the antenna apparatus 100can be made small and thin.

The Second Embodiment

FIG. 4 is a perspective diagram of an antenna apparatus 200 according tothe second embodiment of the present invention, and FIG. 5 is anorthographic projection thereof. The same reference numbers are given tothe components the same as FIG. 2 and FIG. 3, and the explanationthereof is not repeated.

The antenna apparatus 200 includes an antenna unit 202 that is differentfrom the antenna unit 102 of the first embodiment. The antenna unit 202of the second embodiment includes a feeding unit 222 that is differentfrom the feeding unit 122 of the first embodiment.

The feeding unit 222 of the second embodiment includes a feeding plate231 that is made into the form where the plane form of the feeding plate131 (of the first embodiment) is cut at about one-half height H/2.

Since the height of the feeding plate 231 is about a half of the firstembodiment, the feeding unit 202, and therefore the antenna apparatus200, can be made even thinner.

The Third Embodiment

FIG. 6 is a perspective diagram of an antenna apparatus 300 according tothe third embodiment of the present invention, and FIG. 7 is anorthographic projection thereof. The same reference numbers are given tothe components the same as FIG. 4 and FIG. 5, and the explanationthereof is not repeated.

The antenna apparatus 300 of this embodiment includes an antenna unit302 that is different from antenna unit 202 of the second embodiment.Further, the antenna unit 302 of this embodiment includes a feeding unit322 that is different from the feeding unit 222 of the secondembodiment.

The feeding unit 322 of this embodiment include a feeding plate 331 thatis arranged not perpendicular to the printed wiring board 101, but at anangle φ.

In other words, the feeding plate 331 is arranged inclining to thefixing part 132 at the angle φ.

According to this embodiment, the height H2 of the antenna apparatus 300is lower than the height of the antenna apparatus 200 of the secondembodiment by ΔH corresponding to the inclination. In addition, theheight ΔH is expressed as follows.ΔH=H0/2−{(H/2)×sin φ}

Therefore, according to this embodiment, the feeding plate 331 isarranged with a lower profile than H0/2, and the antenna apparatus 300can be made further thinner.

The Fourth Embodiment

FIG. 8 is a perspective diagram of an antenna apparatus 400 according tothe fourth embodiment of the present invention, and FIG. 9 is anorthographic projection thereof. The same reference numbers are given tothe components the same as FIG. 2 and FIG. 3, and the explanation thereof is not repeated.

The antenna apparatus 400 of this embodiment includes an antenna unit402 is different from the antenna unit 302 of the third embodiment.Further, the antenna unit 402 includes a feeding unit 422 that isdifferent from the feeding unit 322 of the third embodiment.Furthermore, the feeding unit 422 of this embodiment includes a fixingpart 432 that is different from fixing part 132 of the third embodiment.

The fixing part 432 of this embodiment holds the feeding plate 231 suchthat the feeding plate 231 can be rotated in the directions indicated byarrow φ11 and arrow φ12.

FIG. 10 is an exploded perspective diagram of the fixing part 432.

The fixing part 432 includes a base 441, a rotation section 442, and asupporting section 443.

The base 441 has nail sections 451 that penetrate the through hole 101 aof the printed wiring board 101 like the fixing part 132, and are fixedby soldering. The base 441 has a concavity 452 that is formedapproximately in the shape of a hemi-sphere.

The rotation section 442 includes a solid sphere section 461 and afeeding plate fixing section 462. The solid sphere section 461 engageswith the concavity 452 of the base 441.

The supporting section 443 is formed approximately in the shape of acircular ring. The feeding plate fixing part 462 penetrates a hole 471of the supporting section 443. The supporting section 443 is fixed tothe base 441 with screws 481, and the like, such that the solid spheresection 461 of the rotation section 442 is supported rotation-free bythe supporting section 443 and the base 441.

A feeding plate fixing part 462 is attached to the solid sphere section461, and is rotationally moved according to the rotational movement ofthe solid sphere section 461. The tip of the feeding plate fixing part462 is fixed to the feeding plate 231 with a screw 491.

In this manner, the feeding plate 231 is supported such that it can berotationally moved in the directions shown by the arrows φ11 and φ12.

Since the feeding plate 231 is supported free to rotate as describedabove, the angle between the feeding plate 231 and the ground plate 121,and the like, can be adjusted according to the transmission/receptionstatus. That is, by rotationally moving the feeding plate 231 in thedirections of φ11 and φ12, alignment between the feeding plate 231 andthe ground plate 121 and antenna directivity can be adjusted. Therefore,transmission and reception can be easily optimized.

In addition, after adjustment, the rotational position of the feedingplate 231 may be fixed by soldering the rotation section 442 to the base441, and the like.

The Fifth Embodiment

FIG. 11 is a perspective diagram of an antenna apparatus according tothe fifth embodiment of the present invention, and FIG. 12 is anorthographic projection thereof. The same reference numbers are given tothe components the same as FIG. 2 and FIG. 3, and the explanationthereof is not repeated.

The antenna apparatus 500 of this embodiment includes an antenna unit502 and the RF circuit unit 103 arranged on a flexible printed wiringboard 501.

The flexible printed wiring board 501 is made of a flexible wiringsubstrate that can be bent, and mounts the electronic parts 111. Theelectronic parts 111 connected by electrically conductive patterns onthe flexible printed wiring board 501 constitute the RF circuit unit103. The RF circuit unit 103 is connected to the antenna unit 502 by themicrostrip line 113 formed on the flexible printed wiring board 501.

The antenna unit 502 is constituted by an electrically conductivepattern formed on the flexible printed wiring board 501, and includes aground plate 521 and a feeding unit 522.

The ground plate 521 is constituted by electrically conductive patterns521 a and 521 b. The electrically conductive patterns 521 a and 521 bare connected to a grounding pattern.

The feeding unit 522 is constituted by an electrically conductivepattern 531 (not shown). The conductive pattern 531 serving as thefeeding unit 522 is shaped like the cross-sectional form of the solidsphere portion of the conventional feeding unit 22 taken along the planecontaining the center axis. In addition, the shape is like thecross-sectional form of the whole feeding unit 22 taken along the planecontaining the center.

When the electrically conductive pattern 531 is designed forcommunications at a frequency between 3.1 and 10.6 GHz that is thefrequency band of UWB, the angle θ of the periphery section to thecenterline C is set at between 40° and 80° (see FIG. 7), and the heightH0 is set at about 25 mm. Here, the height H0 is set at approximatelyλ/4 of the minimum frequency used for transmission and reception.

Further, at this time, the width W is set up so that ground plate 521may become slightly greater than the bottom form of the feeding unit522.

By setting up as described above, the peak value of VSWR can be madesmaller than 3.0 in the 3.1-10.6 GHz range that is the frequency band ofUWB.

Next, the manufacturing method of the antenna apparatus 500 of thisembodiment is described.

FIGS. 13A, 13B, and 13C are perspective drawings for explaining themanufacturing method of the antenna apparatus 500.

First, as shown in FIG. 13A, the electrically conductive patterns 521 aand 521 b serving as the ground plate 521, and the electricallyconductive pattern 531 serving as the feeding unit 522, are formed onthe flexible printed wiring board 501.

Next, the electronic parts 111 are mounted on the flexible printedwiring board 501 as shown by FIG. 13B.

Next, the flexible printed wiring board 501 is bent 90 degrees at theportion indicated by a chain line as shown in FIG. 13C.

In this manner, the antenna apparatus 500 as shown in FIG. 11 and FIG.12 is completed.

According to this embodiment, the feeding unit 522 is made small andthin as compared with the conventional case where the shape of aninverted cone is used. Therefore, the antenna apparatus 500 can be madesmall and thin.

Others

By molding the antenna apparatuses 100 through 500 described above bymolding resin, the dimensions of the antenna apparatuses 100 through 500can be further reduced, due to the wavelength compression effect.

Further, the present invention is not limited to these embodiments, butvariations and modifications may be made without departing from thescope of the present invention.

The present application is based on Japanese Priority Application No.2004-271580 filed on Sep. 17, 2004 with the Japanese Patent Office, theentire contents of which are hereby incorporated by reference.

1. An antenna apparatus, comprising: a ground plate that is shaped likea plate; and a feeding unit that extends from the ground plate at apredetermined angle in reference to the ground plate for a predeterminedlength in a direction that perpendicularly intersects the ground plate;wherein the feeding unit is shaped like a plate extending from one endof the ground plate in the direction that perpendicularly intersects theground plate for the predetermined length.
 2. The antenna apparatus asclaimed in claim 1, wherein a height of the feeding unit measured fromthe ground plate is reduced by removing a portion of the feeding unit,the portion being opposite to the ground plate.
 3. The antenna apparatusas claimed in claim 2, wherein the feeding unit is shaped like asemicircle.
 4. The antenna apparatus as claimed in claim 1, wherein thefeeding unit is arranged not perpendicular to the ground plate.
 5. Theantenna apparatus as claimed in claim 1, wherein the feeding unit iscapable of rotational movement in directions parallel to the groundplate.
 6. The antenna apparatus as claimed in claim 1, wherein thefeeding unit is a plate like member, and is attached to the groundplate.
 7. The antenna apparatus as claimed in claim 1, wherein theground plate is formed by an electrically conductive pattern on aprinted wiring board.
 8. The antenna apparatus as claimed in claim 7,wherein the printed wiring board is made from a high dielectricmaterial.
 9. The antenna apparatus as claimed in claim 1, wherein theground plate and the feeding unit are constituted by a pattern for theground plate and a pattern for the feeding unit, respectively, formed ona flexible printed wiring board, a portion occupied by the pattern forthe feeding unit being bent in reference to a portion occupied by thepattern for the ground plate such that the feeing unit extends for thepredetermined length in the direction that perpendicularly intersectsthe ground plate.
 10. The antenna apparatus as claimed in claim 9,wherein the pattern for the feeding unit is shaped like a semicircle.